The respiratory system, which is responsible for ventilation, is one of the most essential vital systems in the human body. Consider the healthcare impact of a few respiration maladies. In 2009, an estimated 8.2% of Americans (9.6% of children and 7.7% of adults) had asthma, and the prevalence of asthma has increased substantially in recent years. In 2007, asthma accounted for 456,000 hospitalizations and more than 3,447 deaths. Persistent asthma treatment includes the use of long-term control medications (most commonly inhaled corticosteroids [ICS]) to reduce airway inflammation and quick-relief medications for acute exacerbations. While the benefits of asthma treatment generally outweigh the potential risks, these medications can be associated with adverse effects. Additionally, some asthma patients have concerns about asthma medications, and some patients would likely prefer to reduce their use of medication if alternative treatments were available. Twenty-seven percent of children with asthma report using complementary and alternative medicine to manage their asthma, and this approach was usually a breathing technique of some kind. Worldwide, chronic obstructive pulmonary disease (“COPD”) ranked as the sixth leading cause of death in 1990. Mortality is expected to increase due to an increase in smoking rates and an aging population in many countries. COPD is the third leading cause of death in the U.S., and the economic burden of COPD in the U.S. in 2007 was $42.6 billion in health care costs and lost productivity. Many researchers have found that nurse-led breathing exercises in the home are significantly more effective for COPD patients with stage 3 or 4 COPD compared with standard medical care for COPD. The ability to monitor the mechanics of respiration has the potential to have a significant impact on respiratory healthcare treatments and the cost of healthcare. Respiratory diseases usually manifest themselves in abnormal spatio-temporal breathing patterns such as those involving excessive chest or shoulder movement. In addition, monitoring thoracoabdominal or abdominothoracic motion breathing patterns is useful to assess the respiratory health of an individual.
The goal of respiration is to provide gas exchange: to supply oxygen to and remove carbon dioxide from tissues. Pulmonary ventilation refers to the movement of air in and out between the atmosphere and the alveoli. The mechanics of ventilation are mainly driven by the muscles which cause lung expansion and contraction. Spirometry equipment traditionally employed to perform such monitoring usually relies on the patient wearing belts or breathing into tubes.
While some aspects of the mechanics of respiration can be captured by single parameters such as the aforementioned respiration rate, volumes, flows and pressures, all of which can be measured with current spirometry equipment, certain parameters that relate to the motion mechanics localized to certain regions of the respiratory process (e.g., of the respiratory muscles, the diaphragm and the thoracic cavity) are difficult to quantify with existing technology during inspiratory and expiratory maneuvers of various kinds. For example, airflow resistance and compliance may be different for the left bronchial tree when compared to the same present on the right side. This uneven property will manifest as a difference in spatio-temporal signals on the chest surface between the left and right sides of the thoracic cage. Lung volume may be different on one side due to differences in transpulmonary pressures (the pressure difference in the alveoli in the lungs and the intrapleural pressure) from one side to the other. These differences may be the result of infections or various respiratory related disease conditions. As noted above, existing spirometry technologies are unable to monitor such a plurality of parameters because at any given instant in time, they only measure a single parameter of interest (e.g., respiratory volume, respiratory flow, breathing frequency, respiratory flow rate, etc.) and do not provide spatially dependent parameters.
There is a need for improved non-contact methods and systems to quantify and monitor aspects of the spatio-temporal respiration mechanics that remain unaddressed by existing spirometry equipment.
There is a need for identifying and analyzing the multi-dimensional spatio-temporal respiration mechanics for determining problems therewith and to suggest improved mechanics for better subject health. More particularly, there is a need for the monitoring of certain parameters of the respiration mechanics, such as the motion patterns of the respiratory muscles and organs (lungs and diaphragm) involved in the respiratory process.